To improve visibility of runways, taxiways, etc., elevated airport field lights such as: runway, taxiway, threshold edge lights, etc. are customarily used in aviation industry.
Proliferation of airport field lighting is also a result of the tendency for great majority of airports to accept not only daylight but night traffic as well. Thus, depending upon the size of an airport, a number of airfield lights are typically found to be in hundreds or thousands. As such, airport operators typically spend a great deal of time in maintaining airfield lights in compliance with safety and other requirements. These factors contribute, often substantially, to an overall high cost of airport maintenance.
Since the airfield lights are typically of relatively short height, an important problem facing airports in general and relatively small, field airports in particular, is that vegetation, such as weeds, may obscure such lights from pilot's view. Consequently, a pilot may not be able to visually ascertain a position of his aircraft relative to the edge of the runway or taxiway that is marked by the airfield lights. Obviously, such condition could result in safety hazards.
The Federal Aviation Administration has certain minimum standards with respect to the intensity and visibility provided by elevated airport runway, taxiway and threshold edge lights. The necessity to meet these standards has created a need for often expensive specialized equipment and trained personnel to maintain airport runways and taxiways and other airfield lights in operational condition. Typically, there are two different operational steps (and corresponding equipment) involved in removal of vegetation from airport grounds. Initially, a large size equipment, such as industrial lawn mowers, is involved in removal of vegetation from the runways/taxiways and from the strips separating the airfield lights from the runways/taxiways. However, such bulky equipment cannot remove the vegetation from the area in the direct vicinity of the airfield lights. This makes it necessary to utilize another type of smaller equipment for such direct removal of vegetation. Thus, use of such equipment and services of specially trained maintenance personnel are essential to safe operation of airports.
Additionally, to suppress vegetation growing, such chemicals as herbicides and ground sterilizers are used by airport maintenance personnel contributing to ecological pollution.
However, the process of soil sterilization which leads to elimination of vegetation, may result in soil erosion in the direct vicinity of a base of airfield lights. Such process is particularly common for the field airports in the areas having sandy soil where winds and airstreams resulting from operation of aircraft engines blow away soil from the area surrounding the base of the light. This is because, in a sandy soil environment, upon elimination of vegetation, there is very little to keep soil together around the base of the light. Thus, wind blows the soil away, producing depressions around the base of the lights which collect environmental water. This leads to further safety hazards.
Thus, it has been a long felt and unsolved need for a simple, inexpensive and reliable device enabling airport operators to suppress vegetation growth and prevent soil erosion in the area surrounding the base of an airfield light without polluting environment.